In UFC Fight, Mixed Martial Arts and Brain Science Collide

CNN.com—February 10, 2011

Fans of mixed martial arts can’t stop talking about how Anderson Silva took down Vitor Belfort in an Ultimate Fighting Championship title match with a single kick.

The Brazilian fighters started off relatively lightly, circling each other for the first minute of Saturday night’s bout. Belfort briefly took Silva down, but the UFC middleweight champion bounced right back up. Suddenly, Silva threw a left front kick to the jaw that knocked Belfort to the mat, and then threw a couple of punches that seemed almost unnecessary to end the match against the dazed fighter.

Knockouts happen because the brain isn’t completely glued to the skull; it has room for movement. A kick or punch to the jaw can displace it, said Dr. Osric King, sports medicine physician at Hospital for Special Surgery in New York, and Medical Advisor for the New York State Athletic Commission.

For the most part, the brain is secured by blood vessels and nerves that are integrated between the skull and different layers of tissue, he said. When the jaw is kicked with enough force, the brain and nerves reach a critical point where they can’t sustain consciousness. As the blood vessels get stretched out, they’re not able to sustain the continued blood supply the brain may need, and the person may black out immediately.

Doctors examined Belfort afterward and found nothing wrong, the fighter said, and today he has no headache or jaw problems.

The area of the jaw that Silva hit is very vulnerable, and a target every fighter will aim for, but there’s not a lot of science behind why this is a sweet spot. Conducting an experiment on knocking people out in particular ways would be unethical, of course, King said.

There’s no hard science on a recovery period, but athletic organizations follow rough guidelines in accordance with the severity of the injury, King said. After a single knockout involving loss of consciousness, there needs to be a healing process of at least about 60 to 90 days before coming back to fighting, King said. In boxing, a technical knockout usually requires 45 days off. If a fighter goes back in too quickly, he’ll be more susceptible to getting knocked out even more easily, he said.

Some people are a little more prone than others to getting knocked out, or don’t recover as well, King said. Some fighters are said to have a "good chin" — they are better at enduring blows. In those individuals, the brain may have adapted to that kind of injury, or the cumulative damage isn’t as obvious as it is in others, King said.